Put the chiles in a 9-by-13-inch glass baking dish and set aside for stuffing.
Combine the tuna, peas, corn and mayonnaise in a small bowl. Season with salt and pepper.
Stuff the peppers with the tuna mixture. Place back in the baking dish; they should fit snugly. Pour the pickled carrots and jalapeno juice over the stuffed chiles. Let come to room temperature, then cover and chill for 2 hours or overnight. Serve cold.
To char the chiles (or any fresh chile): Put the chiles over a gas flame or underneath the broiler and cook until they are blackened on all sides. Enclose them in a plastic bag and let stand for 10 minutes to steam, which will make them easier to peel. Peel, stem and seed the chiles. Once peeled, the chiles may be chopped, sliced or stuffed.